[DrJava] [ drjava-Bugs-539435 ] Inaccurate reporting of line and column

[<no...@so...>]

Bugs item #539435, was opened at 2002-04-04 14:44
You can respond by visiting: 
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Category: Definitions (source editor)
Group: Annoying
Status: Open
Resolution: None
Priority: 8
Submitted By: Eric E. Allen (eallen)
Assigned to: Jim Van Fleet (bigfleet)
Summary: Inaccurate reporting of line and column

Initial Comment:
This bug applies only to the (thus far) unreleased 
drjava20020404-* and up.

I spent some time looking at, and playing with, the 
new line number code. It's pretty clear that the 
problem is what I call a Liar View: the model seems 
to be correct, but the view isn't displaying it 
properly. In particular, when moving the caret with 
the arrow keys, the line reporting is consistently 
reporting the position_before_ the last line change. 
Also, the current column is reported as 1 at every 
key movement after the first (yet test cases on the 
model side show that the current column is computed 
properly).

Here is my hypothesis: 

The listener for updating the position display is 
registered with the DefinitionsPane. Perhaps the 
DefinitionsPane is notifying the listener of a 
mouse/key movement before the model is updated? This 
would at least explain the lag in the update of line 
positions. The other problems are potentially due to 
race conditions between the model and the listener.

I think that what we really want is for the listener 
to be notified by the GlobalModel directly. But, 
currently, there is no method for notifying 
GlobalModelListeners of position changes (and I'm not 
sure that we really want to notify all listeners of 
every position change).

Unfortunately, I don't have any more time to help 
with this right now. But I suggest commenting out the 
line that sets the text in MainFrame.PositionField 
until this problem is fixed.

BTW, even if the listener is notified by 
DefinitionsPane, shouldn't it be a CaretListener 
instead of a Key- and MouseListener? However, I made 
that change on my copy and it had no effect on the 
problem.

-- Eric




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